1. Field
One embodiment of the invention relates to a telephone system in which telephone terminals and soft phones, etc., achieve voice calls via a network such as an Internet Protocol (IP) network.
2. Description of the Related Art
As described in JP-A 2004-247904 (KOKAI), a telephone system has a message storage function as a basic function of the telephone system. In recent years, telephone systems have become able to store not only voice data but also image data. The aforementioned reference technology sets a compression rate of recording data by paying attention to information on a calling side (calling source).
Many of the IP telephone systems in recent years have presence management functions. Each of these functions manages an attribute at this moment in time of a user every moment for each user. This function may also manage personal information of user's status, such as ‘off seat’/‘on seat’, user's status such as ‘in office’/‘on business trip’, or personal information such as a managerial position and an assigned department. A typical telephone system having the function uses a session initiation protocol (SIP).
As mentioned above, in recent years, the presence management function in the telephone system has attracted attention. Combining the presence management function with a message data storage function presents a possibility to develop a new system application.